"A surprise significant cut, say of 2 million bpd, is needed to push prices back up to $80. And that would have to be accompanied by some newfound discipline in the non-Saudi members," Hepworth said.

The market has been awash with conspiracy theories as to why Saudi Arabia has not already intervened. New York Times columnist Thomas Friedman hinted at "a global oil war under way pitting the United States and Saudi Arabia on one side against Russia and Iran on the other".

Hepworth argued that Saudi Arabia appeared pretty happy with current pricing levels and suggested they were waiting to see where the cut-off point for U.S. production was.

"Time is on their side, they can afford to wait," he said, stressing he was talking months, not years, but added if oil fell below $70 that waiting time "shrinks to weeks".

Tom Nelson, of Investec Global Energy Fund, said he believed Saudi Arabia had allowed the price to fall to incentivize smaller OPEC producers, which often rely on the biggest producer to intervene, to join Riyadh in cutting output.

"They (the Saudis) want to cut but they don't want to cut alone," Nelson said, adding that a cut of between one million and 1.5 million bpd should be sufficient to balance the market.

"The market really wants to see that OPEC is still functioning ... if there is a small cut, with an accompanying statement of coherence from OPEC that presents a united front, and talks about seeing demand recovery, and some moderation of supply growth, then Brent could move up to $80-$90."